以编程方式将类型传递给服务的最佳方法是什么？

Question

Using Angular4 I have created services for different databases. Each databases' actions are the same (kinda like CRUD) but have a different API endpoint (but exactly the same functions.)

I was creating a service for each database but I am thinking there must be a better way to manage this.

Is there a way to pass a "name" to a service during an import or in a component so that the service will know which endpoint should be hit?

Example:

import {ApiService} from '../_services/api.service.ts';

and in the service:

let endpoint = enter code here defined from import of component  
private url = '/api/' + endpoint

Answer 1

Something like

@Injectable()
abstract class ApiService {
  protected endpoint;

  protected get url() {
    return '/api/' + this.endpoint;
  }

  constructor(protected http: Http) {}

  getItems() {
     return this.http(this.url);
  }
}

class SomeService extends ApiService {
  protected endpoint = 'some';
}

Notice that endpoint is defined as a field and url is read-only accessor, this allows to maintain proper order in child class.

A WETter version (also allows child classes to inject additional dependencies) is:

@Injectable()
abstract class ApiService {
  constructor(protected http: Http) {}
  ...      
}

@Injectable()
class SomeService extends ApiService {
  constructor(http: Http /*,  protected some: Some */) {
    super(http);
  }
  ...
}

If same dependency persists in both parent and child class, it should have protected access modifier in parent class only.